• Biomolecules & Therapeutics
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• v.28 no.4
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• pp.337-343
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• 2020

Activation of osteoclast and inactivation of osteoblast result in loss of bone mass with bone resorption, leading to the pathological progression of osteoporosis. The receptor activator of NF-κB ligand (RANKL) is a member of the TNF superfamily, and is a key mediator of osteoclast differentiation. A flavanone glycoside isolated from the fruit of Poncirus trifoliata, poncirin has anti-allergic, hypocholesterolemic, anti-inflammatory and anti-platelet activities. The present study investigates the effect of poncirin on osteoclast differentiation of RANKL-stimulated RAW264.7 cells. We observed reduced formation of RANKL-stimulated TRAP-positive multinucleated cells (a morphological feature of osteoclasts) after poncirin exposure. Real-time qPCR analysis showed suppression of the RANKL-mediated induction of key osteoclastogenic molecules such as NFATc1, TRAP, c-Fos, MMP9 and cathepsin K after poncirin treatment. Poncirin also inhibited the RANKL-mediated activation of NF-κB and, notably, JNK, without changes in ERK and p38 expression in RAW264.7 cells. Furthermore, we assessed the in vivo efficacy of poncirin in the lipopolysaccharide (LPS)-induced bone erosion model. Evaluating the micro-CT of femurs revealed that bone erosion in poncirin treated mice was markedly attenuated. Our results indicate that poncirin exerts anti-osteoclastic effects in vitro and in vivo by suppressing osteoclast differentiation. We believe that poncirin is a promising candidate for inflammatory bone loss therapeutics.

• Molecules and Cells
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• v.40 no.10
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• pp.752-760
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• 2017

A2B adenosine receptor (A2BAR) is known to be the regulator of bone homeostasis, but its regulatory mechanisms in osteoclast formation are less well-defined. Here, we demonstrate the effect of A2BAR stimulation on osteoclast differentiation and activity by RANKL. A2BAR was expressed in bone marrow-derived monocyte/macrophage (BMM) and RANKL increased A2BAR expression during osteoclastogenesis. A2BAR stimulation with its specific agonist BAY 60-6583 was sufficient to inhibit the activation of ERK1/2, p38 MAP kinases and $NF-{\kappa}B$ by RANKL as well as it abrogated cell-cell fusion in the late stage of osteoclast differentiation. Stimulation of A2BAR suppressed the expression of osteoclast marker genes, such as c-Fos, TRAP, Cathepsin-K and NFATc1, induced by RANKL, and transcriptional activity of NFATc1 was also inhibited by stimulation of A2BAR. A2BAR stimulation caused a notable reduction in the expression of Atp6v0d2 and DC-STAMP related to cell-cell fusion of osteoclasts. Especially, a decrease in bone resorption activity through suppression of actin ring formation by A2BAR stimulation was observed. Taken together, these results suggest that A2BAR stimulation inhibits the activation of ERK1/2, p38 and $NF-{\kappa}B$ by RANKL, which suppresses the induction of osteoclast marker genes, thus contributing to the decrease in osteoclast cell-cell fusion and bone resorption activity.

• Molecules and Cells
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• v.23 no.2
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• pp.246-251
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• 2007

Osteoporosis is a common metabolic bone disease characterized by low bone mineral density (BMD) with an increased risk of fracture. Low bone mass results from an imbalance between bone formation by osteoblasts and bone resorption by osteoclasts. Microphthalmia-associated transcription factor (MITF) plays a critical role in osteoclast development and thus is an important candidate gene affecting bone turnover and BMD. In order to investigate the genetic effects of MITF variations on osteoporosis, we directly sequenced the MITF gene in 24 Koreans, and identified fifteen sequence variants. Two polymorphisms (+227719C > T and +228953A > G) were selected based on their allele frequencies, and then genotyped in a larger number of postmenopausal women (n = 560). Areal BMD ($g/cm^2$) of the anterior-posterior lumbar spine and the non-dominant proximal femur was measured by dual-energy X-ray absorptiometry. We found that the MITF + 227719C > T polymorphism was significantly associated with low BMD of the trochanter (p = 0.005-0.006) and total femur (p = 0.02-0.03) (codominant and dominant models), while there was no association with BMD of the lumbar spine. The MITF+228953A > G polymorphism was also associated with low BMD of the femoral shaft (p = 0.05) in the recessive model. Haplotype analysis showed that haplotype 3 of the MITF gene (MITF-ht3) was associated with low BMD of the trochanter (p = 0.03-0.05) and total femur (p = 0.05) (dominant and codominant models). Our results suggest that MITF variants may play a role in the decreased BMD of the proximal femur in postmenopausal women.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.94-102
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• 2007

The ameloblastoma is a common odontogenic tumor of the jaw bone and represents approximately 1% of tumor in the jaw. However, it might be able to infiltrate into the adjacent tissue, causing bony destruction and high recurrent rate. In this study, expression of RANKL and OPG in ameloblastoma in relation to age and gender of patient and recurrence, location of the lesion were examined through immunohistochemisry study. The RANKL and OPG antibody staining were used. The obtained result were as follow. 1. Positive immunoreactivity to RANKL/OPG in all specimens was found. 2. 1n recurrenc, location of ameloblastoma and age, gender of patients using immunohistochemical expression of RANKL. There was not significant difference. 3. 1n recurrence, location of ameloblastoma and age, gender of patients using immunohistochemical expression of OPG. There was not significant difference. In summary, it is suggested that activation of osteoclasts by RANKL is an important mechanism by which ameloblastomas cause bone destruction.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.1
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• pp.13-29
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• 2020

Objectives This study was performed to decide the bone union effect of Hwaweo-jeon on tibia fractured mice. Methods In this study, laboratory experiments were implemented by the stage of in vitro and in vivo. In in vitro, MC3T3-E1 cells were treated with various concentration of Hwaweo-jeon extract (HWJ). To investigate effect of HWJ for osteoblast, relative mRNA expression of 5 substances (alkaline phosphatase [ALP], runt-related transcription factor 2 [Runx2], osteocalcin [OCN], osterix [OSX] and collagen type II alpha 1 chain [Col2a1]) was used as a marker of osteogenesis. In order to determine HWJ's effect for fracture healing, relative gene expression level of ALP, Runx2, OCN, OSX and Col2a1 were used to find out the influence to osteoblast. Furthermore, receptor activator of nuclear factor kappa-B ligand and osteoprotegerin relative mRNA expression were used to estimate the impact to osteoclast. Also, X-ray was used for the purpose of identifying bone union in tibia-fracture mouse model. Results In in vitro experiment, most part of relative mRNA expression were increased compared to control group. In in vivo and in vitro experiment, HWJ induced osteoblast activitation by verifying relative mRNA expression of 5 substances. And in vivo experiment, we can also identify that HWJ triggered osteoclast activation during early stage of tibia fracture. Furthermore, X-ray pictures show noticeable recovery of tibia fracture. Conclusions HWJ extract promotes bone union by facilitating the osteoblast. But, HWJ may occur liver & kidney toxicity over specific concentration. Therefore, when HWJ is applied to human body, doctors have to follow up the liver function test & renal function test of patient.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.997-1004
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• 2005

In bone remodeling imbalances that are caused by increased bone resorption over bone formation lead to adult skeletal diseases. Thus, we have screened various natural products for their ability to regulate the differentiation of osteoclasts to propose candidates for the prevention or treatment of osteoporosis. Scutellaria baicalensis Georgi and Zizyphus Jujuba Miller var. extracts of 140 natural products inhibited the differentiation of RAW264.7 cells into osteoclast, as showed by the reduced number of tartrate resistant acid phosphatase(TRAP)-positive multinucleated cells and decreased TRAP activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.698-704
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• 1998

This study was carried out to investigate the effects of diet of Korean safflower(Carthamus tinctorious L.) seed powder on bone tissue during the recovery of rib-fracture in rats. Male Sprague-Dawley rats of 10 weeks old, weighing 370$\pm$5g, were divided into two groups including the control group(C group, AIN-76 semipurified diet) and safflower seed group(S group, AIN-76 semipurified diet+10% safflower seed powder) and were fed experimental diets for 12 days after adaptation period. After this period, the 9th right rib was fractured surgically and sham-operation was also performed. Rats were fed with experimental diets for up to 30 more days after rib-fracture. The degree of bone repair was evaluated during the recovery period at the 8th, 11th, 16th, 21st, 30th days after the surgical operation by microscopic observation of the fractured rib tissue. In callus formation, the portion of hyaline cartilage was noticably higher in S group than C group. The intracatilagenous ossification was observed at the 8th day in S group, but at 11th day in C group. The intramembranous ossification in callus was widely found over the 8th day to the 11th day in S group, but it was shown over the 11th day to the 16th day in C group. Bone resorption was also occured more rapidly in S group as indicated by large numbers of osteoclasts observed. At the 30th day, most of trabecular bones were disappeared in S group, whereas still shwon in C group over wide ranges of fractured ribs. These results imply that the supplementation of Korean safflower seed powder influences in the recovery of bone fracture by accelerating the process of bone repair.

• YAKHAK HOEJI
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• v.49 no.6
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• pp.495-504
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• 2005

In our study, osteoporosis was induced by ovariectomized in female Sprague-Daweley rats, and the prevention and treatment efficacy of the climacteric disease the postmenopausal Type I pattern was examined by using the experimental substance soybeans and arrowroot. After ovariectomy; the amount of estrogen was found to be reduced by 21.37$\%$ and it showed the tendency to be increased by 4.49$\%$ in T1 (extraction of soybeans group) and 7.62$\%$ in T2 (extraction of ferment soybeans group). The change of bone density, 14 weeks after ovariectomy in the femur, was decreased by 9.33$\%$ in N.C. group, and 5.46$\%$ in T3 (extraction of ferment arrowroot group). As pathological findings, the trabeculae of femur were detected to be abundant as normal and the frequency of the appearance of osteoclasts was very minimal. In the T3, the frequency of the appearance of the trabeculae of femur was increased to the level that could be distinguished. In regard to the accumulation of lipid in the bone marrow, the accumulation of lipid in the bone marrow was low as normal. However, in T3, the decrease to the level that could be distinguished was detected. In addition, in regard to the pathological findings of the uterus, normal uterine tissue findings were detected. In the T3, the minimal atrophy findings were detected. In conclusion, when the T3 was orally administered continuously for 14 weeks, it was thought that a certain proportion of the hormonal balance was maintained that functioned as a substance interfering the accumulation of fat, and it was considered to be of help in the treatment of not only osteoporosis Type I, but also for the prevention and treatment of various endocrinal diseases.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.163-168
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• 2017

Osteoporosis is a metabolic bone disease that is characterized by low bone mass resulting from an increase in bone resorption relative to bone formation. The most current therapies for osteoporosis have focused on inhibiting bone resorption by osteoclasts. The purpose of this study is to develop new anabolic agents for treatment of osteoporosis that have fewer risks compared to conventional therapies. We searched the natural products that were derived from the traditional Asian medicines which have been used for treatment of bone related diseases. Icaritin is a flavonoid glycoside derived from the herb Epimedium which has beneficial effects on bone formation. To determine the effect of icaritin on bone formation, we examined the effect of icaritin on MC3T3-E1 cell proliferation and differentiation. For determining the effects of icaritin on proliferation, we performed the MTT assay using MC3T3-E1 cells. To evaluate whether icaritin could promote the osteogenic differentiation of MC3T3-E1 cells, alkaline phosphatase (ALP) activity and mRNA expressions of Runx2, osteocalcin (OCN), RANKL, and osteoprotegerin (OPG) were determined. Icaritin increased MC3T3-E1 cell proliferation. Icaritin increased the ALP activity of MC3T3-E1 cells on 72 hour culture in osteogenic media. mRNA expression of Runx2 was increased after 24 hour culture with icaritin. mRNA expression of osteocalcin was increased after 72 hour culture with icaritin. In addition, icaritin increased the mRNA expressions of OPG and RANKL. However, icaritin increased the mRNA expression of OPG much more than that of RANKL, and then, it increased the OPG/RANKL ratio. These results suggest that icaritin promotes osteogenic differentiation of osteoblasts and decreases osteoclast formation regulated by osteoblasts.

• International Journal of Oral Biology
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• v.45 no.1
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• pp.15-24
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• 2020

The fruit of Chaenomeles sinensis (Thouin) Koehne (Chaenomelis Fructus) known as "Mo-Gua" in Korea has been commonly used in traditional medicine to treat inflammatory diseases, such as sore throat. However, its effect on bone metabolism has not been elucidated yet. Here, we examined the effect of Chaenomelis Fructus ethanol extract (CF-E) on receptor activator of nuclear factor (NF)-κB ligand (RANKL)-mediated osteoclast differentiation and formation. CF-E considerably inhibited osteoclast differentiation and tartrate-resistant acid phosphatase-positive multinuclear cell formation from bone marrow-derived macrophages and osteoclast precursor cells in a dose-dependent manner. In addition, the formation of actin rings and resorption pits were significantly suppressed in CF-E-treated osteoclasts as compared with the findings in non-treated control cells. Consistent with these phenotypic inhibitory results, the expressions of osteoclast differentiation marker genes (Acp5, Atp6v0d2, Oscar, CtsK, and Tm7sf4) and Nfatc1, a pivotal transcription factor for osteoclastogenesis, were markedly decreased by CF-E treatment. The inhibitory effect of CF-E on RANKL-induced osteoclastogenesis was associated with the suppression of NFATc1 expression, not by regulation of mitogen-activated protein kinases and NF-κB activation but by the inactivation of phospholipase C gamma 1 and 2. These results indicate that CF-E has an inhibitory effect on osteoclast differentiation and formation, and they suggest the possibility of CF-E as a traditional therapeutic agent against bone-resorptive diseases, such as osteoporosis, rheumatoid arthritis, and periodontitis.